The primary goal of this research is to employ observational methods to explore the development of anger expression in peer interactions during middle childhood and early adolescence, and to examine carefully the role of gender and social context. Children who express anger inappropriately are at risk of a variety of psychological disorders, both internalizing and externalizing (Parker & Asher, 1987). However, earlier investigations of aggression have focused on forms of behavior that are more common among boys and social contents where boys behaviors are more likely to be salient (Fry & Gabriel, 1994; Crick & Grotpeter, 1995). Therefore it is not surprising that these constructs serve as better predictors of later outcomes for boys than girls. Observational research on the broad range of ways that girls and boys express anger across a variety of settings would likely help psychologists better understand long-term social adjustment and devise intervention programs for all children who behave aggressively or have difficulty being appropriately assertive. In an investigation currently underway, child participants interact with a same-gender actor in the context of a computer game, where the game is programmed to give the advantage to the actor who is trained to make provoking remarks while winning. These studies will extend this earlier observational research on anger expression in several important ways. Using the method described above, study One will examine anger expression in cross-gender pairs. Study Two will employ a laboratory task that a) seems more consonant with the social concerns of girls than a competitive computer game, and b) pilot research shows elicits more subtle forms with an actor, who has been trained to be provoking by calling attention to herself, making obnoxious comments, and disrupting the game. Because it seems important to determine whether more subtle forms of anger expression are evident in both boys and girls interactions, the design of Study Two will include both male and female pairs of best friends, and provocation by a same and opposite-gender peer. For Study Three, a laboratory task will be observed. Based on findings from the earlier laboratory studies, Study Four will develop methods for naturalistic observation of forms of anger and aggression that are common among girls and boys, in a variety of settings where girls and boys behaviors may be evident.